It is difficult to grasp the scope of fiscal function and policy. The paper first explores fiscal functions based on thoughts of traditional public finance school and public choice school, and then analyzes fiscal functions and polices from political and economic perspectives. With respect to fiscal function and policy, governments at every level should put three aspects into consideration: economic effects after increasing or decreasing public expenditure, the amount of public debt to support capital budgeting vs. self-liquidating speed and payback period of capital construction, and the relationship between democratic politics and fiscal deficit. Therefore, it is suggested that the government should try to find dynamic equilibrium of fiscal functions, carefully evaluate government spending, apply cost-benefit analysis on capital budgeting, and avoid excessive political intervention within budget process.